Added NPE guard for null async executor; fixes gh-2094

spring-cloud-sleuth-instrumentation/src/main/java/org/springframework/cloud/sleuth/instrument/async/LazyTraceAsyncCustomizer.java

@@ -44,10 +44,14 @@ public class LazyTraceAsyncCustomizer extends AsyncConfigurerSupport {
 
 	@Override
 	public Executor getAsyncExecutor() {
-		if (this.delegate.getAsyncExecutor() instanceof LazyTraceExecutor) {
-			return this.delegate.getAsyncExecutor();
+		Executor executor = this.delegate.getAsyncExecutor();
+		if (executor instanceof LazyTraceExecutor) {
+			return executor;
 		}
-		return LazyTraceExecutor.wrap(this.beanFactory, this.delegate.getAsyncExecutor());
+		else if (executor == null) {
+			return null;
+		}
+		return LazyTraceExecutor.wrap(this.beanFactory, executor);
 	}
 
 	@Override

spring-cloud-sleuth-instrumentation/src/main/java/org/springframework/cloud/sleuth/instrument/jdbc/SpanNameProvider.java

@@ -26,6 +26,7 @@ import static java.util.regex.Pattern.compile;
 class SpanNameProvider {
 
 	private static final String DEFAULT_SPAN_NAME = "query";
+
 	private static final Pattern PATTERN_MATCHING_FIRST_WORD_OF_SQL = compile("^([a-zA-Z]+)[^a-zA-Z]?.*$");
 
 	String getSpanNameFor(String sql) {
@@ -47,4 +48,5 @@ class SpanNameProvider {
 
 		return spanName;
 	}
+
 }

spring-cloud-sleuth-instrumentation/src/test/java/org/springframework/cloud/sleuth/instrument/async/LazyTraceAsyncCustomizerTest.java

@@ -54,4 +54,13 @@ public class LazyTraceAsyncCustomizerTest {
 		BDDAssertions.then(executor).isExactlyInstanceOf(LazyTraceExecutor.class);
 	}
 
+	@Test
+	public void should_return_null_when_executor_null() throws Exception {
+		BDDMockito.given(this.asyncConfigurer.getAsyncExecutor()).willReturn(null);
+
+		Executor executor = this.lazyTraceAsyncCustomizer.getAsyncExecutor();
+
+		BDDAssertions.then(executor).isNull();
+	}
+
 }

spring-cloud-sleuth-instrumentation/src/test/java/org/springframework/cloud/sleuth/instrument/jdbc/SpanNameProviderTest.java

@@ -15,6 +15,7 @@
  */
 
 package org.springframework.cloud.sleuth.instrument.jdbc;
+
 import org.junit.jupiter.api.Test;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -22,9 +23,13 @@ import static org.assertj.core.api.Assertions.assertThat;
 public class SpanNameProviderTest {
 
 	private static final String DEFAULT_SPAN_NAME = "query";
+
 	private static final String SPAN_NAME_FOR_SELECTS = "select";
+
 	private static final String SPAN_NAME_FOR_UPDATES = "update";
+
 	private static final String SPAN_NAME_FOR_INSERTS = "insert";
+
 	private static final String SPAN_NAME_FOR_DELETES = "delete";
 
 	@Test
@@ -124,4 +129,5 @@ public class SpanNameProviderTest {
 
 		assertThat(result).isEqualTo(expectedResult);
 	}
+
 }